1. Field of the Invention
The present invention relates to an electronic component mounting device for mounting an electronic component onto a circuit-board.
2. Description of the Prior Art
Conventionally, there have been proposed various kinds of devices for mounting an electronic component such as a chip resistor, a chip multilayer capacitor or the like onto a circuit-board. One of them is well known as a rotary type mounting device which is capable of executing the mounting operation in high speed. The rotary type mounting device includes an intermittently rotatable rotary frame, a plurality of holding members each comprising a suction nozzle etc. mounted on the rotary frame and the like. Each holding member is moved up and down by means of a stationary cam with the rotation of the rotary frame so that an electronic component may be held by the holding member at a location suitable for supplying the electronic component. The electronic component is then conveyed to another location suitable for mounting the electronic component onto the circuit-board by the rotation of the rotary frame so that the electronic component may be mounted onto the circuit-board by moving the holding member up and down.
The applicant of the present invention has proposed Japanese Patent Laid-open Application (Tokkaisho) No. 61-119100 in which, as shown in FIG. 1, each of a plurality of holding members 32 is moved up and down by the operation of a linear motor 33, but not by way of the stationary cam. In FIG. 1, 30, 31, 34 and 35 respectively designate electronic components, a rotary frame, an electronic component supplying device and a circuit-board onto which one or more electronic components are firmly mounted, with the circuit-board 35 being placed on a mounting table 36.
In the conventional mounting device of the type employing therein the stationary cam, however, the position of each holding member in a vertical direction is fixedly determined on the basis of a position where the rotary frame rotates. Accordingly, in the case where various kinds of the electronic components different in height are desired to be mounted onto the circuit-board, pressure to be applied to each electronic component can not be adjusted, thus resulting in that the electronic components are occasionally subjected to cracks or any other damage.
On the other hand, the mounting device of the type employing therein the linear motor, as disclosed in the aforementioned disclosure, can remove the above described problem. However, this kind of device necessitates the linear motors 33 having a relatively large stroke, since the holding members 32 are driven by respective linear motors 33 throughout their entire stroke. Each of the linear motors 33, therefore, inevitably occupies a wide space at a location suitable for mounting the electronic component in spite of the fact that such a location is required to be left unoccupied for a variety of work, thus resulting in poor workability. Furthermore, since each one holding member 32 needs one linear motor 33, the device have been manufactured disadvantageously at high cost. Also, this device needs a complicated electric supply system, since electric power for controlling a plurality of linear motors 33 set on the rotary frame 31 is supplied from a certain fixedly arranged portion.